title: Effects of inhibitors of Toll-like receptors, protease-activated receptor-2 signalings and trypsin on influenza A virus replication and upregulation of cellular factors in cardiomyocytes.
abstract: Severe influenza sometimes causes myocarditis. We recently found that influenza A virus (IAV) infection induces various cellular factors, such as proinflammatory cytokines IL-6, IL-1β and TNF-α, matrix metalloproteinases (MMPs) and ectopic trypsin in mice hearts and in H9c2 cardiomyocytes. The induction of these cellular factors in turn promotes viral replication, myocardial inflammation and cellular damage through their intracellular signal transductions in cooperation with the IAV-induced Toll-like receptors (TLRs) and proteinase-activated receptor-2 (PAR-2) signalings, although the precise nature of these interactions remain obscure. By using specific inhibitors of TLRs and PAR-2 signalings and trypsin inhibitor aprotinin, we analyzed the role of TLR signaling and PAR-2 signaling in the IAV-induced pathological changes in cardiomyocytes. Inhibitors of TLR7/8-Myeloid Differentiation factor 88-nuclear factor-κB signaling and aprotinin effectively suppressed IAV-induced upregulation of proinflammatory cytokines, MMPs, trypsinogen and viral replication. Inhibitor of TLR3-Toll/interleukin-1 receptor domain-containing adaptor inducing interferons-dependent signaling predominantly suppressed the upregulation of interferon-β, a key intracellular host immune response factor. In contrast to the suppressive effect of trypsin inhibitor aprotinin on IAV replication, PAR-2 inhibitor FSY-NH(2), induced marginal upregulation of trypsinogen and subsequent stimulation of IAV replication.
authors.affiliation: Division of Enzyme Chemistry, Institute for Enzyme Research, University of Tokushima, Tokushima, Japan.
authors.forename: Hai-Yan
authors.initials: HY
authors.lastname: Pan
authors.forename: Mihiro
authors.initials: M
authors.lastname: Yano
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kido
mesh_terms: D000818:Animals; D007611:Aprotinin / Q000494:pharmacology; D001483:Base Sequence; D002460:Cell Line; D016207:Cytokines / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects* / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology; D051379:Mice; D008955:Models, Cardiovascular; D009205:Myocarditis / Q000209:etiology / Q000378:metabolism / Q000821:virology; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000502:physiology* / Q000821:virology*; D016328:NF-kappa B / Q000378:metabolism; D009976:Orthomyxoviridae Infections / Q000209:etiology / Q000378:metabolism / Q000821:virology; D012367:RNA, Viral / Q000235:genetics; D044464:Receptor, PAR-2 / Q000037:antagonists & inhibitors*; D015398:Signal Transduction / Q000187:drug effects; D051193:Toll-Like Receptors / Q000037:antagonists & inhibitors* / Q000378:metabolism; D014361:Trypsin Inhibitors / Q000494:pharmacology; D015854:Up-Regulation; D014779:Virus Replication / Q000187:drug effects
chemical_list: D016207:Cytokines; D017931:DNA Primers; D016328:NF-kappa B; D012367:RNA, Viral; D044464:Receptor, PAR-2; D051193:Toll-Like Receptors; D014361:Trypsin Inhibitors; D007611:Aprotinin